Does the Double Slit Experiment, prove, that we live in a simulation?

Originally posted by Jezus
The next level of this experiment is the delayed erasure.

They used the detectors and before looking at the pattern on the back wall (wave or particle pattern) they deleted the information. What they found
was that deleting the information after measurement had the same effect as not measuring at all, a wave pattern.

If they keep the information (but don't look at it) it is a particle pattern.

This proves that the measurement does not collapse the wave function but the existence of information does.

Provide a link to this outlandish claim. I'd be very interested if it were true, but right now it's just words on a screen by someone on ATS.

It's true. I haven't mentioned it, because it complicates things slightly (this is an example of crossing my fingers hoping that no one else here is
so versed in QM that they know about this little quirk). But, yes...erasing the information eliminates the effect of the observation.

This entire problem is akin to the falling tree...

If a tree falls in the forest and no one's around to hear it, does it make a sound?

If a particle passes through a slit and no one's around to observe it, does it form an interference pattern?

This additional fact, then, gives us a bit of a different analogy...

If a tree falls in the forest and no one's around to hear it, but if we record it with a tape recorder and listen to it later, does it make a
sound?

In this case, however, the tape recorder is destroyed before anyone gets a chance to listen to it. Did the falling tree make a sound?

In this case, it depends on how we define 'sound'. If we define it as the perception of a disturbance in the air by our ears, then, no, it didn't
make a sound. But, if we define it as the disturbance in the air, itself, then it did make a sound.

In the case of our quantum experiment, we have the same problem:

If a particle passes through a slit and no one's around to observe it, but if we record the result and observe it later, does it form an interference
pattern?
What if the results are destroyed before anyone gets a chance to observe it?

This time, it depends on our definition of 'observation'. If we define it as our own physical perception of information, then, no, it hasn't been
observed. But, if we define it as the recording of the information, itself, then it has been observed.

Obviously, as this addition to the experiment shows, 'observation' is defined as our own physical perception of the information, and not the
gathering of that information.

But, I want to call your attention to one very important word in that statement: 'physical'.
Our perception of something is still a physical interaction, involving the exchange of photons and whatever else we use to make the observation. We
think it's observation at a distance, but it's not.

The second thing to note is the definition of 'information'. Is 'information' the data, itself, or is it the observation of that data?

The third thing to note is how we define the reaction of the particle and its "choices" to the existence of information. Is the particle tied to a
particular instant in time, as we are, or will it react to actions taken at different points in time?

In this case, we must ask, is the particle truly reacting to our observation of the information, or is it reacting to the existence of the
information, itself? And, does it react to the destruction of that information, even when the information is destroyed in its future?
Because we may react solely to what's going on around us at a single instant in time, but why must particles be held to the same constraints?

Originally posted by Jezus
The next level of this experiment is the delayed erasure.

They used the detectors and before looking at the pattern on the back wall (wave or particle pattern) they deleted the information. What they found
was that deleting the information after measurement had the same effect as not measuring at all, a wave pattern.

If they keep the information (but don't look at it) it is a particle pattern.

This proves that the measurement does not collapse the wave function but the existence of information does.

Originally posted by CLPrime
It's true. ...

Well, the first three sentences are true, I'd like to see a source for the 4th one. It seems to presume that the measurement and the existence of
information derived from the measurement are separate entities. I'm not sure this is true at the quantum level and especially where quantum
entanglement is involved.

Here's a link to the paper on the quantum erasure experiment which also looked at delayed erasure:

We have presented a quantum eraser that uses a Young double slit to create interference...We recovered interference using the entanglement of
photons s and p.

We have also investigated this experiment under the conditions of delayed erasure, in which the interfering photon s is detected before photon p. In
as much as our experiment did not allow for the observer to choose the polarization angle in the time period after photon s was detected and before
detection of p, our results show that a collapse of the wave function due to detection of photon s does not prohibit one from observing the expected
results.

In the delayed choice quantum eraser discussed here, the pattern exists even if the which-path information is erased shortly after, in time, the
signal photons hit the primary detector. However, the interference pattern can only be seen retroactively once the idler photons have already been
detected and the experimenter has obtained information about them, with the interference pattern being seen when the experimenter looks at particular
subsets of signal photons that were matched with idlers that went to particular detectors.

So even though these experiments do have some strange
and unexpected results, we actually don't see the interference pattern in the total pattern of signal photons at the primary detector. We can only
deduce the pattern from a subset of that total. These experiments are done with entangled photons, and we have already shown that entanglement is a
strange phenomenon that can allow certain things to happen faster than the speed of light. However, even in these experiments, the information is
still not available faster than light:

The total pattern of signal photons at the primary detector never shows interference, so it is not possible to deduce what will happen to the
idler photons by observing the signal photons alone, which would open up the possibility of gaining information faster-than-light (since one might
deduce this information before there had been time for a message moving at the speed of light to travel from the idler detector to the signal photon
detector) or even gaining information about the future (since as noted above, the signal photons may be detected at an earlier time than the idlers),
both of which would qualify as violations of causality in physics.

In this case, we must ask, is the particle truly reacting to our observation of the information, or is it reacting to the existence of the
information, itself? And, does it react to the destruction of that information, even when the information is destroyed in its future?

I think
you're asking the right questions. I don't have an answer and I'm not sure anybody really does, but I think it might be fair to say that we don't
fully understand quantum entanglement yet, and since these experiments involve entangled particles, we have to admit that we don't know exactly what
is going on with the entanglement, or what Einstein called "spooky action at a distance". I suspect someday we'll understand entanglement a whole lot
better than we do today and when we do, these experimental results with entangled photons will hopefully make more sense to us.

Forgive me if I am wrong, but by the sound of it this post seems to indicate your earlier claims are incorrect and that it is indeed the act of
observing or recording the information that changes the effect rather than interference via the method itself similar to the wind tunnel analogy.

Not quite...my earlier posts are right in their context.
This addition is merely a technicality that, as explained by Arbitrageur, is made fatally complicated by the method of the experiment, the recording
of the information, the destruction of that information, and the method used to determine the results given the destruction of the information.

Specifically, it's the involvement of entanglement which leads to the seemingly observation-based results, because entanglement is the very embodiment
of reaction-by-observation. However, that doesn't mean that entanglement is reaction-by-observation. I actually have my own personal theory on
how entanglement works, which I explained a couple days ago in another thread. If I'm
right, then this new experiment is no more reaction-by-observation than the basic double-slit experiment. And, even if I'm not right, there are bound
to be other theories to explain entanglement without invoking reaction-by-observation.

So, my earlier posts are not wrong, and they are still not wrong even in this example. It's just that this example complicates things by involving one
of the most mysterious (and least-understood) phenomenon in Quantum Mechanics.

Here is a very good illustration of a basic version of
the quantum eraser experiment.

The difference between this and the delayed-choice version is that, in this case, the information about which side the photon "chose" to pass on is
learned by a polarizer between the slits and the screen... while, in the delayed-choice experiment, the polarization is done on an entangled photon
pair not going through any slits, indirectly affecting the photon passing through the slits, while allowing the information to be gathered indirectly
after the photon has reached the screen and (presumably) after it has already either formed or not formed an interference pattern.
The knowledge of this information seems to affect the outcome of the experiment after the experiment has already occurred.

Again, the problem is with the nature of entanglement, in addition to how little we know about the physical nature of wave functions, the collapse of
those wave functions, and wave-particle duality.

Originally posted by traditionaldrummer
The Double Slit Experiment is currently and vigorously being used as the leverage to pass through all manner of new age/metaphysical claims. Although
it's a common tactic to use quantum mysteries as a kind of foundation for mystical nonsense I'm unsure why this particular experiment is currently
being paraded around with such enthusiasm.

In the case of this thread the DS experiment is used to justify a claim that "we live in a simulation". I'm very skeptical that the experiment
indicates any such thing.

Intriguing and very agreeable, but allow me to add a caveat?

Mystics are responding to a perception, and to assume that it is a mis-perception may be an error.

I, too, want measurable, cause-and-effect type assurance of what one describes as real; but Newtonian physics fails us in complex science as well as
in the complexity of what it is to be human. Quantum physics is much more promising... in both regards.

If the examination of mystical, or "paranormal" or metaphysical (my preferred term as a theologian) experience and perception can find a suggestion
of verification and/or explanation in science-- even if only superficially understood science--it is a far more beneficial thought process than the
wild speculation which typically ensues.

Much better that speculative metaphysics pays attention to the only now budding quantum physics, than busy itself with wrapping one's head in foil to
keep the aliens guessing.

So, physicists tell us the math suggests (or even proves) that at least eleven dimensions exists instead of only four... to which speculative
metaphysics answers, "Yes, we thought that might be so; and it not only matches our experiences, but may help us to better understand them." The
dichotomy between science and religion/spirituality is a false one and an unnatural one to which far too many subscribe.

Oh, and in my ignorance of modern physics, pardon me for asking: Does the unexpected third line of "hits" have any change in its relative
separation from the other two (or its apparent focus) if the wavelength of the light is changed, and if so, is there a correlation?

Originally posted by Frira
So, physicists tell us the math suggests (or even proves) that at least eleven dimensions exists instead of only four...

I don't know about
that. The string theorists who say that may in some cases still be in the physics department, but what I hear them saying is they might get moved to
the math department instead of the physics department, unless they can come up with some scientific proof.

There's nothing wrong with the math. It's the lack of experimental verification that's the problem. There may indeed be 11 dimensions, or, there
may not, and there may be a completely different explanation.

Originally posted by Arbitrageur
There's nothing wrong with the math. It's the lack of experimental verification that's the problem.

Mongo like math.

Originally posted by CLPrime
String Theory is pure math, with very little, if any, testable physics.

Mongo trust math.

And as much as I would like to take the results of the Double Slit experiment as evidence of something other than verification that light particles
somehow also behave as waves, I am inclined to suspect that is all it indicates (and I'll probably read up on it and probably learn I am wrong).

Yet, happily, the measuring phenomenon leaves me thinking of Schrodinger's Cat at a deeper level-- maybe it is not just a thought experiment after
all?

Math is great. I love math, too. But, math is not physics. There might be several ways to mathematically describe the universe, but, if none of them
can be physically tested or applied, then what good are they?
That's the problem with String Theory. It's all bones, no meat. Until we perfect inter-dimensional travel, it's got no testable hypotheses or
practical applications.

Now, the double-slit experiment. I mentioned earlier that the condition-specific wave-particle duality idea, itself, is a little outdated. Here's
what the current picture of wave-particle duality is:

All particles are formless, point-like regions described solely by a set of quantum numbers and other intrinsic properties (like charge and
energy/mass). They behave probabilistically, so their location at any given instant is defined only by how "probable" it is that the particle is
located there. This can be seen most clearly in electron probability clouds, which define the most likely location for an electron "orbiting" the
nucleus of an atom. They don't move in predictable ways - one instant, they could be on one side of the atom, while, the next instant, they could
appear on the other. All we can truly say is how "probable" it is for the electron to be at any given location.
And this applies to all particles. Even photons travelling in a straight line. In this case, however, the probability forms a wave through space, and
the result is that the photon appears to travel in a wave-like manner, when, in fact, it is travelling "straight" through a wave-shaped probability
cloud (like ripples on a pond, where the crests represent regions where the photon is most likely to be, and the troughs represent regions where the
photon is least likely to be). This wave-shaped probability cloud is called the wave-function.

In the double-slit experiment, it is the wave-function which interferes with itself when passing through the slits, and the photons are then bound to
follow this interference pattern.

All these experiments do, then, is destroy and/or restore the wave-function, which is different than destroying and/or restoring the photon's own
interference pattern.

Math is great. I love math, too. But, math is not physics. There might be several ways to mathematically describe the universe, but, if none of them
can be physically tested or applied, then what good are they?
That's the problem with String Theory. It's all bones, no meat. Until we perfect inter-dimensional travel, it's got no testable hypotheses or
practical applications.

Now, the double-slit experiment. I mentioned earlier that the condition-specific wave-particle duality idea, itself, is a little outdated. Here's
what the current picture of wave-particle duality is:

All particles are formless, point-like regions described solely by a set of quantum numbers and other intrinsic properties (like charge and
energy/mass). They behave probabilistically, so their location at any given instant is defined only by how "probable" it is that the particle is
located there. This can be seen most clearly in electron probability clouds, which define the most likely location for an electron "orbiting" the
nucleus of an atom. They don't move in predictable ways - one instant, they could be on one side of the atom, while, the next instant, they could
appear on the other. All we can truly say is how "probable" it is for the electron to be at any given location.
And this applies to all particles. Even photons travelling in a straight line. In this case, however, the probability forms a wave through space, and
the result is that the photon appears to travel in a wave-like manner, when, in fact, it is travelling "straight" through a wave-shaped probability
cloud (like ripples on a pond, where the crests represent regions where the photon is most likely to be, and the troughs represent regions where the
photon is least likely to be). This wave-shaped probability cloud is called the wave-function.

In the double-slit experiment, it is the wave-function which interferes with itself when passing through the slits, and the photons are then bound to
follow this interference pattern.

All these experiments do, then, is destroy and/or restore the wave-function, which is different than destroying and/or restoring the photon's own
interference pattern.

Thank, you explain that very well --in a way I can understand.

Not mathematically, merely conceptually, I keep coming back to the notion that the theoretical dimension provides us with an understanding which both
and at once is counter-intuitive and fitting our experience (even in the mundane):

An object has width and length but we perceive no depth (such as we perceive watching TV or looking at a picture on a wall), the existence of depth is
hinted at-- and even if not perceived its existence explains our perception in that we have a presumption that unseen or not, that third dimension is
implied.

So, I sit here before a screen emitting photons and the following is apparently true: I am able to focus at the point where the photon is observed as
a particle, because after that point it is a non-particulate wave effecting the space around it through which it passes. Otherwise, I would see a
series of opaque particles streaming from the screen which emits them (similar to thousands of tiny lasers shining through a fog). That the particle
reacts by changing from particle to wave and then back again when it encounters either matter or detection-- based upon observation,
electro-mechanical or biological-- that suggests to me that the observation is inter-dimensional in its interaction with the particle or wave.

For a theologian, that evidences that we are much more than we appear.

Since there is no spacial-temporal interaction, and yet change is made, It seems that both it and the observer have existence beyond the common
spacial-temporal-- and existence in one or more unobservable but mathematical necessary dimension(s).

Take that one more step, if observation, alone, causes a change from wave to particle, I cannot escape the assumption that light exists to be
observed-- and that is a very anthropocentric concept. It means something.

Of course, the idea here is that a photon (and every other particle) is a wave and a particle at the same time. Though, the term "particle" is a
little misleading. It used to be a physical object. Now, it's just point in space having spin, charge, and mass. And the location of this point in
space at any given time is defined by the wave-function.

Personally, I think we'd be having better luck coming up with working quantum theories if we started thinking of the wave-function as what's real and
not the particle, itself. Both exist, but the particle is merely information contained at a point in space... the wave function defines the physical
existence/location and motion of that information.

In general, I'm quite open to the possibility of a limited anthropocentric universe (in fact, my life is based on belief in such a universe), but we
need to be careful if we're going to try to use physics (especially quantum mechanics) to prove such a concept.

Of course, the idea here is that a photon (and every other particle) is a wave and a particle at the same time. Though, the term "particle" is a
little misleading. It used to be a physical object. Now, it's just point in space having spin, charge, and mass. And the location of this point in
space at any given time is defined by the wave-function.

Personally, I think we'd be having better luck coming up with working quantum theories if we started thinking of the wave-function as what's real
and not the particle, itself. Both exist, but the particle is merely information contained at a point in space... the wave function defines the
physical existence/location and motion of that information.

In general, I'm quite open to the possibility of a limited anthropocentric universe (in fact, my life is based on belief in such a universe), but we
need to be careful if we're going to try to use physics (especially quantum mechanics) to prove such a concept.

edit on 22-6-2011 by CLPrime
because: (no reason given)

But the experiment suggests that the photon indeed ceases to be a wave and instead is a true particle when measuring which slit is passed. The old
(and maybe still current-- I am not reading cutting edge, nor particularly technical material-- Wikipedia and spin-off's from there) view was that
photons can change state, but never be in both states at once.

I suppose wave and particle are probably analogues rather than truly descriptive terms, which I think was your point to me.

I also suspect a primary misconception I am holding is that the wave properties are of the thing. I suppose the reality is that wave refers to an
artifact of the effect of the thing upon space. But I cannot reconcile that to the experiment except to say I prefer the idea that space was effected
by the measurement rather than the photon. Now that I think about it-- that works a lot better with the erasure phenomenon as well.

tohu wa bohu: Perhaps the photon's passing disturbs the harmony of the union of matter and anti-matter which we call nothingness [or so I
extrapolate from something I read of Hawking (I think it was) long ago].

As for physics and proving any anthropocentric concept-- whatever is true will be to the delight of man. I'm very fond of a concept I took from
James Michener's Space: It is up to the individual to reconcile what he knows to be true with what he believes to be true.

You've been very patient and very kind, and I am smarter for it; but I think I am being selfish and not adding to the discussion.

Is is possible that the "changing states" of the photon, that you're referring to, is with respect to its quantum state - which, as far as a photon
in concerned, is its spin? This can either be spin-up (+1) or spin-down (-1), but not both.

As far as wave-particle duality, it's common to think that a particle is a particle under some conditions and a wave under others. It's actually
always a combination of both, and the method of observation is what isolates one side or the other.

I guess the first step in understanding this is to abandon the idea that a "particle" is a physical object. It's not, It's merely a set of
intrinsic data (spin, charge, and mass) located at some point in space. It's like data on a computer... what you see as an entire working program is
really just a bunch of magnetic 1s and 0s on a disk. In the same way, what we measure to be a physical particle is really just a bunch of properties
"hard-coded" into a given point in space.
And this data is free to move around, within bounds. These bounds are described by the wave-function, which defines the probability of the data being
found in any given region or location.

The wave-function, then, could be seen as a cage. It defines where the data (which we observe as a particle) is allowed to go, and the data is unable
to go outside that wave-shaped cage.

The double-slit experiment causes the wave/cage to interfere with itself as it passes through the slits. When the particle/data follows that
wave/cage, then, it follows the interference pattern. The particle/data, itself, is not a wave, but its boundaries are defined by a wave-shape.

I didn't think I could make wave-particle duality this simple

If I start talking about posits, primeons, and the Prime-Ruggles Hypothesis, slap
me, please.

Originally posted by Frira
I also suspect a primary misconception I am holding is that the wave properties are of the thing. I suppose the reality is that wave refers to an
artifact of the effect of the thing upon space. But I cannot reconcile that to the experiment except to say I prefer the idea that space was effected
by the measurement rather than the photon. Now that I think about it-- that works a lot better with the erasure phenomenon as well.

Your thought is exactly what scientists first said, "The measuring device must be interfering with the wave function to create a particle
pattern."

So this is why they did the delayed erasure. If they measure but delete the data it has the same effect as not measuring at all.

This proves that the act of measuring does not itself collapse the wave function.

I wished I had the tools to do this experiment. First thing I would like to try is what if one slit is longer than the other one and what is one is
wider than the other one and what if you do both at the same time having one longer and wider than the other one? Now as for the detector part of the
experiment put it on the output side after the slits and now what kind of pattern do you get. If I had the tools I could have some real fun with this.
I heard about this double slit experiment many years ago and it has alway made me wonder.

I would like to refer people to this thread that started nearly a couple of years ago, that has great insights to it from The Matrix Traveller. Who
puts across some valid and, "out of the box" ideas that relates to the OP and at the same time. If one looks in to the math sees that a whole new
way of understanding light emerges in ones understanding. And if should be bold to say a new paradigm in the way we have come to think about light

This content community relies on user-generated content from our member contributors. The opinions of our members are not those of site ownership who maintains strict editorial agnosticism and simply provides a collaborative venue for free expression.